Granular soap compositions containing carbamide



United States Patent F 3,130,166 RANULAR SOAP COMPOSITIONS CONTAINING CARBAMIDE Lawrence L. Schwalley, Whittier, Calif., assignor to United States Borax & Chemical Corporation, Los Angeles, Calif., a corporation of Nevada No Drawing. Filed Feb. 5, 1958, Ser. No. 713,290 Claims. (Cl. 252-110) This invention has to do with granular washing compositions that contain granular soap as an important constituent. This application is a continuation-in-part of my copending patent application, Serial Number 659,498 filed May 16, 1957, under the same title, now abandoned.

Such compositions ordinarily contain one or more major constituents in addition to soap, including, for example, synthetic detergents, trisodium phosphate, borax, and substantially inert fillers such as talc, wood flour, starch and the like. The term granular is employed throughout the present specification and claims with reference to compositions consisting of a large number of discrete solid particles, regardless of the fineness of division of the particles. For example, the term includes such materials as are commonly described as powdered.

In many such compositions it is desirable that the granular ingredients, including the soap, be finely divided. That is desirable, for example, to insure rapid solution of the water soluble components when the composition is used. Fine division of the granular materials is also desirable, particularly in a preparation intended for washing the hands, in order to provide a smooth and agreeable texture of the composition both before and after it is wet with water.

In previous soap compositions of the type described, it was generally not practicable to employ soap that was finely enough divided to fully satisfy such requirements. Although methods were known for producing granular soap of the desired fineness, it could not be used offectively, primarily because of its tendency when first Wet to form gummy lumps. Such lumps become smeared over the object being washed, and are slow to dissolve and difficult to rinse oif. That difficulty is particularly troublesome in granular soap compositions for washing the hands, since the lumps-tend to adhere to the skin and may dissolve only after protracted rubbing. In order to avoid such lumping of the composition during use, it was previously not feasible in most granular soap compositions to employ soap particles as fine as was otherwise desirable.

Furthermore, even when the granular soap was not es pecially finely divided, previous compositions tended to produce lumping upon being wet if the ratio of soap to the other components was as high as was otherwise desirable for some purposes.

The present invention has successfully overcome those difficulties in a very simple and economical manner. The invention thus permits the preparation of effective and satisfactory granular soap compositions in which the soap granules are substantially as finely divided as may he desired. The invention also permits the preparation of granular soap compositions containing a far larger proportion of soap than was previously feasible.

I have discovered that lumping of a granular soap composition upon use can be controlled by including in the soap composition a suitable proportion of carbamide.

The carbamide is most effective for the present purpose when it is added as a solid granular component which is physically mixed with the other components of the composition. The carbarnide is then capable of dissolving completely as soon as the composition is wet, and the effective rate of solution of the carbamide is not 3,130,166 Patented Apr. 21, 1964 ice significantly limited by the solution behavior of other ingredients of the composition.

Carbamide is useful for reducing lumping of positions when present in proportions from about 0.5% to about 20% of the soap in the composition. Percentage figures here and throughout the present specification refer to percentages by weight.

A further aspect of the invention has to do with the fact that certain additives which may potentially improve the character of granular soap compositions tend to promote lumping of the composition when the latter is used. For that reason it has previously not always been feasible to employ such additives in effective concentrations Without sacrifice of other desirable qualities. By providing a novel, effective and economical means of controlling the lumping of granular soap compositions, the invention permits free and elfective use of additives of the described type.

A suitable type of polyacrylamide, for example, consists essentially of the high molecular weight polymer hydrolytes produced by homopolymerization of acrylamide and by its copolymerization with up to about 15 percent by weight of other suitable monomers such as alkyl esters of acrylic acid and methacrylic acid, methacrylamidc, styrene, vinyl acetate, acrylonitrile, methacrylonitrile, vinyl alkyl ethers and vinyl and vinylidene chloride. From about 0.8 to about 10 percent of the amide groups of the polymer are typically replaced by carboxyl groups. Such polyacrylamide is typically charcterized by a viscosity of at least 4 centipoises at a temperature of 215 C. for an aqueous 0.5 percent by weight solution adjusted to a pH of 3 to 3.5. Polyacrylamide of that illustrative type is available commercially under the trade name Separan 2610 Polyacrylamide is known to act as an effective emollient when added to granular soap compositions in typical concentrations from about 0.1% to about 2%. I have discovered, however, that polyacrylamide also tends to promote lumping of the soap composition during use. That is particularly troublesome in just those compositions in which the emollient action of the polyacrylamide is most desirable, namely, in good quality compositions Which are designed especially for washing the hands, and which contain a generous proportion of soap in the form of particles that are as finely divided as is practicable. My invention solves that difficutly, and makes it feasible to provide fully satisfactory granular soap compositions which possess in combination the three desirable characteristics: the smooth feel and rapid action of a relatively high concentration of very finely divided soap particles; the useful emollient quality contributed by polyacrylamide; and the rapid, free and uniform spreading of the wetted composition on the hands without lumping.

Many granular soap compositions include one or more granular materials in addition to the soap, which add body and may improve the chemical or physical action of the composition. Among such body-contributing materials, borax is known to be particularly useful and effective. Other granular body-contributing materials include cornstarch, sugar, wood flour, vermiculite, talc, calcium phosphate and potassium sulfate, for example, and mixtures of two or more materials. The soap component in the compositions of the invention may comprise any suitable type of alkali metal salt of a long chain fatty acid, such as is normally obtained by saponification of natural fats and oils. Such soaps as coconut soap, stearate soap, tallow soap and cottonseed soap are illustrative. Many compositions comprise a mixture of two or more such soap types. Other known additives may be included as may be desirable, such as perfume, foaming agents, coloring agents, emollients and other cosmetic agents, for exsoap com quently incorporated during preparation of one or more of the principal granular components.

The invention is particularly useful in connection With States Standard Sieve Sizes, Which is employed throughout the present specification and claims. And as the soap particles of such prior the lumping problem becomes progressively more troublesome. The invention completely solves that difficulty by addition of an appropriate proportion of carbamide.

other major comabsence of minor is intended, the quantity and nature of ponents, if any, and the presence or soap and 65 percent tallow soap, cal of good quality hand soap compositions. positions of Table 1 are simplified Soap to +30 mesh) Borax (-30 to +100 mesh) Carbamide, granular gredients other than soap; and that difficulty increases progressively with the soap content and with the fineness of the soap particles. Addition of tion of carbamide completely eliminates that difiiculty,

carbamide, for example from on the Weight of the soap.

On the other hand, previously available compositions nsisting substantially wholly of granular soap of com- Table 2 D E F G H Soap to +200 mesh) pereent 15 35 60 75 Borax to +325 mesh) (1 83 60 33 16 Polyacrylamide d 1 1 1 1 1 Carbamide, granular do 1 4 6 8 14 and 2 That is, carbamide the compositions or somewhat finer In the compositions size is comparable to, than, that of the other componets.

For example, able 2, but in upon elimination of the fine particles from the composition, as by causing them to agglomerate into larger particles or to adhere to larger particles already present. For example, if a very finely divided soap composition is not treated to remove any soap dust that is present, as by sieving or air separation, the dust is found to persist even in the presence of carbamide under normal packaging and storing conditions. Whereas such dust is not usually desirable in a commercial product, the presence of a suitable proportion of carbamide, as already described, overcomes its normal tendency to produce lumping of the composition during use.

A particularly important field of utility of the invention relates to granular soap compositions for washing the hands. I have discovered that addition of only a few percent of carbamide to such compositions sometimes permits very considerable improvement in the quality of existing compositions, by controlling lumping and thus permitting the compositions to be modified in respects that were previously impracticable. Such improvements include, in particular, reduction of the particle size, especially of the soap, to improve the feel of the composition during use and to accelerate its action; increase of the soap content; and addition of components such as polyacrylamide. In many instances only a relatively slight modification of that type is required to provide an important improvement in quality of the composition; and under such conditions only a few percent of carbamide is needed. At the same time, merely by appropriate increase of the carbamide content, the invention permits for the first time in actual practice freedom to carry out such variations as have been described to any degree that may reasonably be desired.

A particularly convenient and effective range of nonlumping compositions for washing the hands comprises from about 20% to about 50% granular soap of a particle size predominantly finer than about 30 mesh and of a type suitable for toilet use such, for example as from to 40 percent coconut soap and from 90 to 60 percent tallow soap; from about 50% to about 80% of bodygiving material, preferably borax of a particle size predominantly finer than about 40 mesh; and an amount of carbamide corresponding to from about 1% to about 10% of the soap in the composition.

The specific examples given above are intended only as an illustration of the invention and not as a limitation upon its scope, which is defined in the appended claims. Many changes can be made in the particulars of the described compositions without departing from the proper scope of the invention. In particular, any type of soap suitable for hand use, including those mentioned, may be employed, and the amount of carbamide may be varied within the general limits indicated to produce products having a wide variety of detailed characteristics.

I claim:

1. A free-flowing granular washing composition consisting essentially of at least 10% of granular soap predominantly finer than about 30 mesh, and carbamide in sufticient quantity to substantially prevent lumping of the composition during use, the amount of carbamide in the composition being from about /2 to about 20% of the granular soap in the composition.

2. A free-flowing granular washing composition consisting essentially of more than about 30% of granular soap predominantly finer than about 30 mesh, and carbamide in sufficient quantity to substantially prevent lumping of the composition during use, the amount of carbamide in the composition being between about /2% and about 20% of the granular soap in the composition.

3. A free-flowing granular washing composition consisting essentially of granular soap predominantly finer than about 30 mesh and carbamide, the amount of carbamide in the composition being from about 5% to about 20% and being sufficient to substantially prevent lumping of the composition during use.

4. A free-flowing granular washing composition consisting essentially of at least about 10% of granular soap predominantly finer than about 30 mesh, between about 0.1% and about 2% of a polyacrylamide emollient which tends to promote lumping of the composition during use, and carbamide in sufficient quantity to substantially prevent such lumping, the amount of carbamide in the composition being from about /2% to about 20% of the granular soap in the composition.

5. A free-flowing granular washing composition consisting essentially of from about 20% to about 50% of granular soap of a particle size predominantly finer than about 30 mesh, from about 50% to about of granular borax of a particle size predominantly finer than about 40 mesh, and granular carbamide in sufficient quantity to substantially prevent lumping of the composition during use, the amount of carbamide in the composition being from about 1% to about 10% of the soap in the composition.

References Cited in the file of this patent UNITED STATES PATENTS 1,716,347 Richl et a1 June 4, 1929 2,423,449 Heald et al July 8, 1947 2,465,346 Bodman Mar. 29, 1949 2,689,166 Rust et al. Sept. 14, 1954 2,781,320 Jelinek et a1. Feb. 12, 1957 2,805,205 Touey et a1 Sept. 3, 1957 2,940,935 Reich et al. June 14, 1960 OTHER REFERENCES Schwartz et al.: Surface Active Agents, Interscience Publishers, Inc. (1949), pages 117 and 235. 

5. A FREE-FLOWING GRANULAR WASHING COMPOSITION CONSISTING ESSENTIALLY OF FROM ABOUT 20% TO ABOUT 50% OF GRANULAR SOAP OF A PARTICLE SIZE PREDOMINANTLY FINER THAN ABOUT 30 MESH, FROM ABOUT 50% TO ABOUT 80% OF GRANULAR BORAX OF A PARTICLE SIZE PREDOMINANTLY FINER THAN ABOUT 40 MESH, AND GRANULAR CARBAMIDE IN SUFFICIENT QUANTITY TO SUBSTANTIALLY PREVENT LUMPING OF THE COMPOSITION DURING USE, THE AMOUNT OF CARBAMIDE IN THE COMPOSITION BEING FROM ABOUT 1% TO ABOUT 10% OF THE SOAP IN THE COMPOSITION. 